Flat plate heat exchanger and flat plate therefor

ABSTRACT

A flat plate heat exchanger and heat exchange plate members for use therein, the heat exchanger having a support structure which includes one or more elongate support members; the plate members each having a generally flat plate portion formed of a heat conductive material, a recess formed in an edge portion thereof for accommodating an elongate support member, and a flexible arm formed in association with the recess and arranged for flexing in a direction which is in the plane of the plate member for snap coupling and decoupling with the elongate support member, such that the plate member is supported thereby.

This application is the U.S. national phase of International PCTApplication No. PCT/IL99/00024, filed Jan. 14, 1999, which designatedthe United States. PCT/IL99/00024 claims priority of Israeli PatentApplication No. 122956, filed Jan. 16, 1998.

BRIEF DESCRIPTION OF THE INVENTION

The present invention relates to flat plate heat exchangers generally,and, in particular, to flat plates and stacks of flat plates, employedtherein.

BACKGROUND OF THE INVENTION

Flat plate heat exchangers are well known, and generally include astacked plurality of generally flat, metal, heat exchange plates. Theplates are supported in a generally parallel, vertical orientationbetween a base plate and a pressure plate, by means of a lower elongatecarrying member, and an upper elongate guide member. The plates havegenerally U-shaped openings formed at their upper and lower outer edges,through which the elongate members extend, in a generally horizontaldirection, so as to support the plates therebetween. It will beappreciated that the openings are shaped so as to enable mountingthereof between the elongate members, and such that they do not becomedislodged therefrom, during assembly of the stack or during disassemblythereof.

A further consideration in securing a stack of heat exchanging plates ina flat plate heat exchanger is that the stack should ideally be fixatedto a support structure so that no movement at all is possible, eitherbetween the plates, or between the plates and the support structure.This is due to the fact that any such movement can cause undesirableforces to be applied to liquid conduits extending in contact therewith,through the heat exchanger, thereby damaging them and, possibly causingmechanical failure thereof.

There exist in the art various solutions for ensuring secure fasteningof the plates to the guide member, once they have been mounted inengagement therewith.

Among known attempts to solve the above problem is that described inU.S. Pat. No. 4,804,040 to Berqvist et al. Berqvist et al describe aplate heat exchanger, seen in FIG. 1A, having a plurality of heatexchange plates (i), which are arranged between a base plate (ii) and apressure plate (iii), and which are supported by a lower carrying bar(iv). The lower carrying bar (iv), and an upper guide bar (v) extendthrough open-form recesses (not shown) in the respective lower and upperportions (vi) and (vii), respectively, of the plates (i).

At least the upper edge of each heat exchange plate (i) is provided withat least one transverse lug which is coplanar with the remainder of theplate, and which extends transversely into the recess so as to form apartial constriction thereof, thereby to assist in retaining the heatexchange plate (i) in engagement with the guide bar (v). The lug isdescribed as being flexible enough to be bent aside, transversely to theplane of the plate, thereby to permit insertion of the guide bar (v)through the constriction and into the recess, and to spring back afterthe bar (v) has been inserted.

Among disadvantages inherent in the above-described heat exchange platesare the fact that it is required to maneuver each plate so as to forceit onto the guide bar with a force that is sufficient to bend the lugs.This not only requires the use of a fair degree of force, but, in theevent that too much force is exerted, the lugs can be bent too much sothat they do not “spring back” into position. Furthermore, the nature ofthe connection of the plates is such that the support bar and guide barare both absolutely necessary in order to immovably lock the plates in astack arrangement.

SUMMARY OF THE INVENTION

The present invention seeks to provide a heat exchange plate for use ina flat plate heat exchanger, wherein minimal force is required toassemble the individual plates, and wherein the plates can be “snapped”into predetermined positions so as not to become substantially dislodgedduring assembly or disassembly.

A further aim of the invention is that the heat exchange plates beinterlockable, thereby minimizing the number of support members thatneed to be provided.

There is thus provided, in accordance with a preferred embodiment of theinvention, a flat plate heat exchanger and a heat exchange plate for usetherein, wherein the heat exchanger includes a support structuretypically having a base member; a movable pressure member arranged forselectable spacing relative to the base member; and elongate supportapparatus between the base member and the pressure member.

There is also provided a plurality of heat exchange plates, each ofwhich includes

-   -   a generally flat plate portion formed of a heat conductive        material; and    -   one or more support engagement portions formed in conjunction        with the flat plate for permitting snap coupling between the        plate member and the elongate support apparatus, such that the        flat plate member is supported thereby,    -   wherein the support engagement portions include one or more        resilient members arranged for flexing in a direction which is        both lateral to the direction of coupling and substantially        parallel to the plane of said plate member.

Additionally in accordance with a preferred embodiment of the presentinvention, the support apparatus has a known width, and the supportengagement apparatus has a recess formed in a predetermined edge portionof the plate member and terminating in an opening located at the edge,wherein the recess is configured to at least partially accommodate thecross-section of the support apparatus, and wherein the supportengagement apparatus also includes one or more lateral protrusionspartially extending laterally across the recess, thereby, in the absenceof at least a predetermined lateral flexure force, preventing couplingor de-coupling of the plate member from the support apparatus.

Further in accordance with a preferred embodiment of the presentinvention, the support apparatus has an opening of known width, and apredetermined edge portion of the plate member is configured for entryinto the opening, and wherein the support engagement apparatus alsoincludes a pair of lateral protrusions, the distance therebetween beinggreater than the width of the opening in the support apparatus, thereby,in the absence of at least a predetermined lateral flexure force,preventing coupling or de-coupling of the plate member from the supportapparatus.

Additionally in accordance with a preferred embodiment of the presentinvention, wherein one or more of the lateral protrusions is formed onthe one or more resilient members.

Further in accordance with a preferred embodiment of the presentinvention, the plate member is formed from folded sheeting, and hasformed therein, adjacent to the one or more resilient members, a shapedopening which is bordered by a pair of side walls which extend atpredetermined non-perpendicular angles, outwardly from the plane of theplate member, such that the plate members are nestable.

Additionally in accordance with a preferred embodiment of the presentinvention, there is also provided a fixator member for insertion intothe shaped opening, the fixator member being configured such that, whenthe plurality of the plate members are arranged in a nested stackwhereby the side walls of the shaped opening of each plate member aredisposed within the shaped opening of an adjacent one of the platemembers, insertion of the fixator member into the shaped opening of theplate member located at the end of the stack causes a lateral flexure ofall of the resilient members so as to cause them to forcibly engage thesupport apparatus, and further, so as to cause the side walls of theshaped openings of the plate members to engage the side walls of theshaped opening of the plate member adjacent thereto.

Further in accordance with the present invention, the plate member isformed from folded sheeting, and the plate member has formed therein,adjacent to the one or more resilient members, a shaped opening which isconfigured such that, when the plurality of plate members are arrangedin a stack, the shaped opening of all the plate members are aligned inmutual registration. Additionally, the heat exchanger also includes oneor more locking members insertable transversely through the shapedopenings of the stack; the one or more locking members and shapedopenings being configured such that, insertion of the locking memberinto the aligned openings causes a lateral flexure of all of theresilient members so as to cause them to forcibly engage the supportapparatus.

Preferably, there are provided two resilient members, and a pair oflocking members which are insertable transversely through the alignedshaped openings of the stack.

Most preferably, the two members are arranged symmetrically about therecess.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be more fully understood and appreciated fromthe following detailed description, taken in conjunction with thedrawings, in which:

FIG. 1A is a general view of a PRIOR ART flat plate heat exchanger, asdisclosed in U.S. Pat. No. 4,804,040;

FIG. 1B is a pictorial view of a flat plate useful in a plate heatexchanger, constructed in accordance with a first embodiment of theinvention, and having support member engagement portions aligned alongthe longitudinal axis of the plate;

FIG. 1C is a pictorial view of a flat plate similar to that of FIG. 1B,except having support member engagement portions located at the cornersof the plate;

FIG. 2A is an enlarged pictorial view of a central engagement portion ofthe flat plate seen in FIG. 1B, having a form fitting engagement recess,configured to fit the support member of a heat exchanger assembly whenfully engaged therewith, seen in partial engagement;

FIG. 2B is an enlarged pictorial view of a central engagement portion ofthe flat plate seen in FIG. 1B, having a form fitting engagement recess,configured to fit the support member of a heat exchanger assembly whenfully engaged therewith, seen in partial engagement, in accordance withan alternative embodiment of the invention;

FIGS. 3–7 are pictorial views of a central engagement portion of a flatplate, also having a form fitting engagement recess, constructed inaccordance with additional embodiments of the invention;

FIGS. 8 and 9 are enlarged pictorial views of dual engagement portionsof flat heat exchange plates, configured to engage a pair of supportmembers of a heat exchanger assembly when fully engaged therewith,constructed in accordance with two alternative embodiments of theinvention;

FIG. 10 is a pictorial view of a flat plate useful in a plate heatexchanger, having three corner support engagement portions, constructedin accordance with a further embodiment of the invention;

FIGS. 11, 12 and 13 are illustrations of corner engagement portionsformed in accordance with three different embodiments of the invention,and such as may be employed in plates for mounting onto dual or triplesupport member arrangements;

FIG. 14 is a partial isometric view of a nestable heat exchange plateformed from folded metal sheeting, in accordance with yet a furtherembodiment of the invention;

FIG. 15A is a pictorial illustration showing initial mounting onto asupport of a stack of nestable plates as seen in FIG. 14, wherein theplates are seen to be in an alternating arrangement;

FIG. 15B is a view similar to that of FIG. 15A, but showing initialnesting of the plates;

FIG. 15C is an enlarged view of the portion of FIG. 15B indicatedtherein by arrow 15C;

FIG. 15D is a view of the stack of FIGS. 15A and 15B in a position offull nesting;

FIG. 15E is an enlarged, schematic end view of the engagement portionsof the nested plates as seen in FIG. 15D;

FIG. 16 is a view of a stacked plurality of nestable plates as seen inFIG. 14, but wherein the plates are stacked in a non-alternatingarrangement, in accordance with an alternative embodiment of thearrangement;

FIG. 17 is a pictorial view of a portion of a flat plate heat exchangerhaving a stacked plurality of heat exchange plates formed generally asseen in FIG. 5, but including additional locking means for locking theplates onto the support member, in accordance with an alternativeembodiment of the invention;

FIG. 18 is an enlarged view of the engagement portion of a single plateseen in FIG. 17;

FIGS. 19A and 19B are schematic views of a portion of the stack of FIG.17, showing partial and complete locking of the plates to the supportmember, respectively;

FIG. 20 is a pictorial view of a flat plate useful in a plate heatexchanger, similar to the plate depicted in FIG. 1B, but having a pairof support member engagement portions arranged so as to permit up to apredetermined thermal expansion of the plate; and

FIG. 21 is a pictorial view of a flat plate similar to that seen in FIG.20, but showing use with a pair of support members, one of which has aprismatic cross-section.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to the construction of flat plates usefulin conjunction with a flat plate heat exchanger. With the exception ofthe plates themselves, support apparatus therefor, and means for lockingthe plates to the support apparatus, the overall heat exchanger isgenerally as known in the art, and as shown and described above inconjunction with FIG. 1A, in relation to U.S. Pat. No. 4,804,040 toBerqvist et al., the contents of which are incorporated herein byreference.

During the entire description that follows, the plate members of theinvention are described as having portions for engaging one or moresupport members. Single support members are denoted in the drawings bythe letter S, while multiple support members are denoted S′, S″ and S′″,as appropriate. These support members correspond, as appropriate, tohorizontal supports or guides which extend between a base plate (ii) anda pressure plate (iii) (FIG. 1A), and are not intended to specificallylimit the use of any of the described plate embodiments either to acarrying bar (iv) or an upper guide bar (v) (FIG. 1A), or to anyalternative support means to which it may be desired to attach the platemembers of the invention. These may include, for example, elongate screwmembers (not shown) which may be extended through a stack of platemembers, thereby to provide both fastening of the plates and also to actas guides therefor. There may also be additional structural elementswhich extend between a base plate (ii) and pressure plate (iii); these,however, are outside the scope of the present invention and thus are notdescribed herein.

Referring now to FIG. 1B, there is shown a flat plate member, referencedgenerally 100, for assembly with a plurality of similar plate membersinto a stack, such as known in the art, for use in a flat plate heatexchanger. Plate member 100 is preferably rectangular, and has paralleledges 102 and 104, which, when plate member 100 is assembled in avertical position, are oriented at the top and bottom of the platemember, respectively. Plate member 100 preferably also has parallel sideedges 106 and 108, extending between the top and bottom edges 102 and104.

Referring briefly to FIG. 1C, there is shown a plate member 100′, whichis identical to plate member 100 (FIG. 1B), except that it has supportmember engagement portions which are located at the corners of theplate, rather than centrally, as in FIG. 1B. All portions of platemember 100′ are denoted by reference numerals used in conjunction withthe description of FIG. 1B, and, therefore, no further description ofFIG. 1C is provided herein, specifically.

Referring now also to FIG. 2A, a support member engagement portion 110is located centrally with respect to top edge 102, and is formed so asto engage support member S by being urged thereagainst in a generallynormal direction, and, thereafter, being retained in engagementtherewith. Engagement portion 110 is constituted by a recess 112 formedin top edge 102, which is formed so as to engage and at least partiallycontain support member S. As seen in the drawings, there is provided apawl 114 which protrudes inwardly into recess 112, thereby to define aconstriction at the recess outlet, referenced generally 116. As seen inFIG. 1B, the width W1 of the constriction is smaller than the diameterD1 of support member S, such that support member S cannot normally passthrough the constriction in a lateral direction, indicated bydouble-headed arrow 118 (FIG. 2A).

In order to permit a snap coupling and decoupling between plate member100 and to support member S, pawl 114 is mounted onto a flexible arm 120which receives its flexibility by virtue of the provision of an elongateopening 121 located generally tangentially to recess 112. Pawl 114, byvirtue of being formed on arm 120, is operative to apply a resistiveforce component to support member S when pawl 114 is brought intocontact therewith.

As seen in FIG. 2A, however, in the presence of a greater and opposingforce, flexible arm 120 is operative to flex outwardly in the plane ofthe plate member 100, in the direction indicated by arrow 122. Thiscauses a momentary widening of the normally constricted opening, andthereby permits entry or exit of the support member S into the recess112, depending on whether the opposing force is an engagement ordisengagement force.

A further feature of the arrangement seen in FIG. 1B is that recess 112is form-fitting, such that its rounded inner portion 124 has a radius ofcurvature which is similar to the external radius of curvature of thesupport member S. Moreover, the pawl 114 is preferably positioned tosubstantially remain in touching engagement with support member S, evenwhen support member S is in full touching engagement with rounded innerportion 124. This substantially reduces the potential for accidentaldislodgment of plate members 100, during assembly of a stack thereof andduring disassembly thereof.

With further reference now to FIG. 1B, it is seen that bottom edge 104may also be formed with an engagement portion 110′ for engagement with asupport member S′. Engagement portion 110′ may be identical toengagement portion 110, and is thus not described again herein indetail. It will be appreciated that, in the case in which plate member100 is provided with top and bottom engagement portions 110 and 110′, itmay be fastened to support members S and S′ by positioning themdiagonally between these two members, and bringing the plate member to avertical position, thereby to rotate recesses 112 and 112′ into fullengagement with support members S and S″, respectively.

It will be appreciated, however, that in many arrangements, a platestack will be adequately supported merely by virtue of the top edgeengagement with support member S, and that each plate member 100 may bepositioned merely by a substantially lateral snap coupling with respectto the support member.

Referring now to FIG. 20, there is shown a flat plate member, referencedgenerally 1100, for assembly with a plurality of similar plate membersinto a stack, such as known in the art, for use in a flat plate heatexchanger. Plate member 1100 is generally similar to flat plate 100(FIG. 1B), and is thus described herein solely with regard todifferences with respect thereto. Portions of plate 1100 having similarcounterpart portions in plate 100 are indicated herein by similarreference numerals, but with the addition of a “1” prefix.

It is seen that plate member 1100 has first and second edge locatedsupport member engagement portions 1110 a and 1110 b which are generallysimilar to support member engagement portions 110 of plate member 100(FIG. 1B), except each having a pair of inwardly-facing pawls 1114. Thepresent embodiment of the invention is characterized, however,particularly by the spacing apart of first and second engagementportions 1110 a and 1110 b along the illustrated Y axis, so as to befurther apart than the spacing between the support members S1 and S2.While first and second engagement portions 1110 a and 1110 b are bothlocated along the Y axis, it will be appreciated that one or both ofthem need not necessarily be located along this axis, and that there maybe provided more than the two engagement portions illustrated.

The described spacing results in a gap, denoted “e”, which facilitatesthe insertion of the plates at an angle, as well as enabling thermalexpansion of plate member 1100 without substantially stressing thesupport structure of which support members S1 and S2 form a part.Typically, gap e need be no more than 1–2 mm, although it may be of anypredetermined magnitude. It will also be appreciated that the spacingbetween the stack support members may be changed in any given stack soas to provide a gap e, preferably with respect to one edge-locatedsupport engagement portion, only.

It is thus seen that, in the illustrated embodiment of the invention,first engagement portion 1110 a engages the associated support S1 in atight fitting mating engagement, substantially preventing movement ofthe plate member 1100 along either the Y axis, or along the illustratedX1 axis, perpendicular to the Y axis. Second engagement portion 1110 b,however, engages its associated support S2 so as to substantiallyprevent movement of the plate member 1100 along the illustrated X2 axis,perpendicular to the Y axis, while permitting expansion of the platerelative thereto along the Y axis.

It will be appreciated by persons skilled in the art that theillustrated plate member 1100 may be oriented in any desired direction,whereby first and second engagement portions 1110 a and 1110 b,respectively, may be either in respective up and down orientations, orin respective down and up orientations, or in any other desired plane.

Referring now briefly to FIG. 21, it is seen that flat plate member 1100may be used in conjunction with a support S3 which is not round, butprismatic, in the illustrated case having a generally squarecross-section, as long as its cross-sectional shape has surfaces orother portions which may be grippingly engaged with pawls 1114 and/orinner portion 1124.

Referring briefly to FIG. 2B, there is seen a support member engagementportion 110 a, which is generally similar to that of FIGS. 1B, 1C and2A, and which bears reference numerals which denote portionscorresponding to portions appearing in FIG. 2A by similar referencenumerals, except with the addition of the suffix “a” or “b”.Furthermore, the engagement portion 110 a is described specifically onlywith regard to differences between it and engagement portion 110 of FIG.2A.

It is thus seen that support member engagement portion 110 a of thepresent embodiment includes a flexible arm 120 a, which has formedtherewith a lug 119 which faces generally away from the recess 112 a.In-plane depression of the lug 119, away from support member S, as byuse of a user's thumb, as seen, widens the constriction defined betweenpawl 114 a formed on flexible member 120 a, and a further pawl 114 b,formed on the side wall of recess 112 a, wherein pawls 114 a and 114 bface laterally inward across the opening of the recess 112 a.

Referring now to FIGS. 3–7, there are illustrated support memberengagement portions which are generally similar to that of FIGS. 1B, 1Cand 2A, and each of which is thus described herein only with regard tofeatures particular thereto.

Referring briefly to FIG. 3, the functions of pawl 114 and flexible arm120 of FIGS. 1B and 2A are provided by forming a generally form-fittingrecess 3112, which is constricted by provision of a rubber-like orelastomeric element 3113 which is fastened to plate member 3100 suchthat a pawl-shaped end portion thereof, referenced 3114, extendsinwardly into recess 3112.

In FIG. 4, there is seen a support member engagement portion 4110 whichis different from the arrangement of FIGS. 1B and 2A both with regard toprovision of an integrally formed pawl 4114 located on an inner edge4115 of recess 4112, while flexible arm 4120 is provided, in the presentexample, without a pawl, and also with regard to the depth of recess4112 which, in the present embodiment is deeper than that recess 112 ofFIGS. 1B and 2A.

Referring now to FIG. 5, the illustrated support member engagementportion 5110 has a recess 5112 which is formed between a pair ofpawl-bearing flexible arms 5120, so as to be symmetrical.

With reference now to FIG. 6, there is seen a support member engagementportion 6110 which has a pair of pawl-bearing flexible arms 6120, butbetween which is defined a flattened recess 6112. It is seen that thisrecess is configured for form-fitting attachment to a support member Swhich has a profile with a broad, flattened base, such as a triangle.

In FIG. 7, the illustrated support member engagement portion 7110 is anasymmetrical dual arm arrangement. Engagement portion 7110 has a first,flexible arm 7120 a, and a second, flexible arm 7120 b. First arm 7120 ais generally similar to flexible arm 120 (FIGS. 1B and 2A), and hasformed thereon a single, inward-facing first pawl 7114 a. Second arm7120 b is longer and thus more flexible than first arm 7120 a, and hasformed thereon a pair of pawls 7114 b and 7114 b′; upper pawl 7114 bbeing located generally opposite first pawl 7114 a, and lower pawl 7114b′ being located therebelow. This arrangement enables engagement of thesupport member S in either a lower, form-fitting position, or, as shownby way of example, in an upper position, between the three pawls 7114 a,7114 b and 7114 b′.

It will be appreciated by persons skilled in the art that any suitablecombination of any of the features of the various support memberengagement portions shown and described above in conjunction with any ofFIGS. 1B–7, as well as any variations thereof which also provide theabove-described type of snap coupling of plate members with a supportmember, are included within the scope of the invention.

Referring now to FIG. 8, there is shown the upper edge portion 202 of aflat plate member 200, for assembly with a plurality of similar platemembers into a stack, such as known in the art, for use in a flat plateheat exchanger.

Upper edge portion 202 has dual support member engagement portions 210which are spaced apart, typically so as to be located adjacent to thetop corners of plate member 200, which are formed so as to engagesupport members S and S′ by being urged thereagainst in a generallynormal direction, and, thereafter, being retained in engagementtherewith.

Each engagement portion 210 is generally similar to engagement portion110, shown and described above in conjunction with FIGS. 1B and 2A,except that, in the present embodiment, the recesses 212 are notnecessarily form fitting, and flexible arms 220 receive theirflexibility by virtue of being formed along side edges 106 and 108,respectively.

It will be appreciated that, in order to provide snap coupling of theplate member with support members S and S′, inward-facing pawls 214,mounted onto flexible arms 220, are spaced apart by a width W2 which isless than the dimension D2 which is the distance between the twooutermost points of the support members S and S′, as shown in FIG. 8. Itwill be appreciated that dimensions W2 and D2 correspond functionally todimensions W1 and D1 in the embodiment of FIGS. 1B and 2A, and providefor engagement and disengagement of support members S and S′ by means ofa generally in-plane pushing or pulling action of the plate memberrelative to the support members.

Referring now to FIG. 9, there is shown the upper edge portion 9202 of aflat plate member 9200, for assembly with a plurality of similar platemembers into a stack, such as known in the art, for use in a flat plateheat exchanger.

Upper edge portion 9202 has dual support member engagement portions 9210which are spaced apart, typically so as to be located adjacent to topcorners 9203 of plate member 9200, which are formed so as to engagesupport members S and S′ by being urged thereagainst in a generallynormal direction, and, thereafter, being retained in engagementtherewith.

Each engagement portion 9210 is generally similar to engagement portion110, shown and described above in conjunction with FIGS. 1B and 2A,except that, in the present embodiment, the recesses 9212 are notnecessarily form fitting, and first and second pawls 9214 and 9214′ areprovided so as to be outward-facing. It is further seen that, whilefirst pawl 9214 is provided on a flexible arm 9220, second pawl 9214′ isformed on an immovable outward facing edge portion 9220′, which isrigidly connected to the remainder of the plate member 9200 via a shapedportion 9121′. The purpose of providing shaped recess 9121′ is so as topermit nesting of a plurality of heat exchange plates, generally asdescribed hereinbelow in conjunction with the embodiments of FIGS.14–15E.

It will be appreciated that, in order to provide snap coupling of theplate member with support members S and S′, pawls 9214 and 9214′ arespaced apart by a width W3 which, in the present embodiment, is greaterthan the dimension D3 which is the distance between the two closest orinnermost points of the support members S and S′, as shown in FIG. 9. Itwill be appreciated that dimensions W3 and D3 correspond functionally todimensions W1 and D1 in the embodiment of FIGS. 1B and 2A, and providefor engagement and disengagement of support members S and S′ by means ofa generally in-plane pushing or pulling action of the plate memberrelative to the support members.

Referring now to FIG. 10, there is shown a plate member, referencedgenerally 300, which has first, second and third support memberengagement portions, respectively referenced 310, 310′ and 310″,arranged for snap coupling with respective support members S, S′ and S″.Engagement portions 310, 310′ and 310″ may be of any suitable snap typeof construction, and are pictorially exemplified by the constructionshown and described hereinbelow in conjunction with FIG. 13.

It will be appreciated, however that, in the present embodiment, inorder to mount plate member 300 on all three support members, it isinitially necessary for first engagement portion 310 to be at leastpartially engaged with support member S. Subsequently, the plate member300 is rotated generally about support member S, as indicated by arrows313, so as to provide engagement of second and third engagement portions310′ and 310″ with respective support members S′ and S″.

Referring now to FIGS. 11, 12 and 13, there are seen three exemplaryplate member corner details which may be useful in conjunction with anyof the dual or triple support member arrangements, seen in FIGS. 8, 9 or10.

Referring briefly to FIGS. 1B-13, it will be appreciated that any of theconstructions shown and described in conjunction therewith may be formedeither from totally flat metal sheeting, or from folded metal sheeting.

Referring now to FIG. 14, however, there is shown the upper edge portion1402 of a nestable flat plate member 1400, for assembly with a pluralityof similar plate members into a stack, such as known in the art, for usein a flat plate heat exchanger. Upper edge portion 1402 has a singlesupport member engagement portion 1410 which is located centrally withrespect to top edge 1402, and is formed so as to engage support member S(not shown) by being urged thereagainst in a generally normal direction,and, thereafter, being retained in engagement therewith. As in theembodiment of FIGS. 1B and 2A, engagement portion 1410 is constituted bya recess 1412 formed in top edge 1402, which is formed so as to engageand at least partially contain support member S. Recess 1412 is boundedby first and second pawls, referenced 1414 and 1414′, whose function isto form a constriction, referenced 1416, similar to constriction 116shown and described above in conjunction with FIGS. 1B and 2A. It isfurther seen that, while first pawl 1414 is provided on a flexible arm1420, second pawl 1414′ is formed on an immovable inward-facing edgeportion 1420′, which is spaced from the remainder of the plate member1400 via a shaped recess 1421′. Plates 1400 are arranged for attachmentto and detachment from support member S by means of the snap couplingmechanism described above in conjunction with FIGS. 1B and 2A, and whichis thus not described again herein.

It is seen that opening 1421 preferably has a pair of side walls 1423 aand 1423 b extending away from the flat sheet portion 1401, so as to beangled slightly across the opening 1421. Shaped recess 1421′ ispreferably of a similar size to opening 1421 and has similarly shapedside walls 1423′; the side walls 1423′ are, however, rigidly spacedapart by a continuum 1425′ of metal sheeting. Accordingly while innerside wall 1423 a can be displaced towards outer side wall 1423 b,thereby to narrow the width of the opening 1421, the width of opening1421′ is fixed.

It will thus be appreciated that opening 1421 and shaped recess 1421′can be used so as to enable convenient nesting of a stack of platemembers 1400, whether this is provided by alternating the openings 1421and recesses 1421′ in adjacent plate members 1400, as shown anddescribed below in conjunction with FIGS. 15A–15E; or by aligning theplate members 1400 in a single, uniform orientation, as described inconjunction with FIG. 16.

Referring now to FIGS. 15A–15B, there is shown a series of steps bywhich plate members 1400 are mounted onto support member S, in analternating arrangement, so as to be resiliently gripped in recesses1421.

In FIG. 15A, a plurality of plate members 1400 are seen to have beensnap coupled to support member S, such that each opening 1421 is alignedwith and arranged between a pair of recesses 1421′. The plate members1400 are then moved together by sliding them along support member S, soas to become initially nested, but not yet compacted together into astack.

As seen in FIG. 15B, and in enlarged view in FIG. 15C, prior tocompaction of the plate members 1400, in view of the compressivegripping force applied by flexible arms 1420, the alternating platemembers 1400 are slightly displaced laterally, relative to the supportmember. It can thus be seen that, pawl tips 1414 a and 1414′a arearranged in an undulating or stepped pattern.

Referring now to FIGS. 15D and 15E, once the plate members have beencompacted together into a stack, referenced generally 1450, flexiblearms 1420 of the plate members 1400 are locked inwardly against supportmember S, by virtue of the rigid shaped recesses 1421′ being insertedinto openings 1421 (FIG. 15E), such that, as seen, particularly in FIG.15E, all the pawl tips 1414 a and 1414′a are locked firmly against thesupport member. This serves to interlock each plate member with theplate member adjacent thereto, and all the plate members together, andthus also to fixate the complete stack with respect to the supportmember, in a predetermined, position, thereby to obviate the necessityof providing further support or locking means.

It will be appreciated by persons skilled in the art that, this featureis of particular importance, ensuring that no movement of the stack canoccur with respect to working-fluid carrying conduits (not shown)extending through the heat exchanger. If such movement were to occur, asin prior systems, it could cause mechanical damage and possibly failureof these conduits. The absolute fixation of the plates and stack withrespect to the remainder of the heat exchanger structure essentiallyprevents such mechanical damage from occurring.

Referring now briefly to FIG. 16, there is seen a plurality of platemembers 1400 arranged such that all the openings 1421 thereof are inmutual registration. It will thus be appreciated that, due to thegenerally conical arrangement of side walls 1423 a and 1423 b,compaction of the plate members brings the side walls 1423 a and 1423 bof adjacent plate members into a nesting arrangement. Subsequentinsertion into the opening 1421 of the end plate member 4200, of asuitably shaped fixator member, depicted schematically at 1452 as beingtrapezoidal, causes the side walls 1423 a and 1423 b of all of the platemembers 1400 to expand, thereby locking together the plate members 1400,and also locking them in contact with the support member S.

Referring now to FIG. 17, there is seen a flat plate heat exchanger,referenced generally 17100, which includes a base plate 17102, a movablepressure plate 17104, a support member S extending therebetween, and astack 1750 of heat exchange plate members 1700, mounted onto supportmember S, between base plate 17102 and pressure plate 17104. It is seenthat base plate 17102, pressure plate 17104, and plate members 1700, areformed so as to enable insertion therethrough of preferably a pair ofelongate locking members 1706 and 1708. Each of locking members 1706 and1708 has a first length L1 which is relatively thin, a second length L2which is relatively thick, and a waist portion L3 which tapers from thesecond length to the first length.

Referring now also to FIG. 18, it is seen that each plate member 1700has a form-fitting centrally-located support member engagement portion,referenced generally 1710, which is generally similar to engagementportion 5110, shown and described above in conjunction with FIG. 5.Accordingly, engagement portion 1710 of the present embodiment isdescribed specifically only with respect to the modifications relativeto engagement portion 5110 of FIG. 5.

It is seen that each opening 1721 which serves to define flexible arms1720 and 1720′ also has formed in side edges 1723 a, 1723 b, 1723′a and1723′b thereof, two pairs of opposing rounded notches 1725, each pairforming two opposing arcs of a circle. More particularly, the two pairsof notches 1725 are formed so as to enable insertion therethrough oflocking members 1706 and 1708 having locking portions whose diameter ‘d’exceeds the diameter of the circle formed by the notches when flexiblearms 1720 and 1720′ are in an at rest position.

It will be appreciated that, while a pair of flexible arms 1720 and1720′ are described, together with their associated openings 1721, anduse of two locking members 1706 and 1708, it is also envisaged that, inaccordance with an alternative embodiment of the invention, a singleflexible arm only may be provided, with a single opening 1721 and asingle locking member 1706 or 1708, for use therewith.

Referring now also to FIGS. 19A and 19B, assembly of the stack 1750 isnow described. Initially, after the plate members 1700 have beenfastened to the support member S in accordance with the techniquedescribed above in conjunction with FIGS. 1B and 2A, first length L1 offirst locking member 1706 is inserted through a suitably providedaperture in base plate 17102, and inserted into the notches 1725 formedin a selected opening 1721.

As seen in FIG. 19A, the diameter of the circle defined by the pair ofengaged notches 1725 is smaller than the diameter of the thicker lengthL2 of first locking member. Continued insertion of the locking member1706 leads to insertion of the thicker length L2 between notches 1725,thereby to cause a flexure of flexible arm 1720′ towards support memberS. Subsequent insertion of the second locking member 1708 in a similarmanner, through the notches 1725 of the other openings 1721 of the stackof plate members, causes a similar flexure of the other flexible arm1720′ towards support member S. As engagement portion 1710 is formfitting, such that recess 1712 and support member S have substantiallyequal radii of curvature, and as locking members extend, as shown,through base plate 17102 and pressure plate 17104, full insertion ofboth locking members 1706 and 1708 causes the plate stack 1750 to befirmly locked into position in the heat exchanger 17100 (FIG. 17).

It will be appreciated that, in the present embodiment, while it ispreferabl that the engagement portions 1710 be form-fitting, plateshaving a non-form-fitting construction may also be employed, and stillprovide the desired locking.

It will further be appreciated that, any of the features exemplified inconnection with any of the embodiments shown and described hereinabovein conjunction with any of FIGS. 1B–19B, may be usefully combined ormodified, while retaining the above-described inventive features of theinvention.

It will yet further be appreciated, by persons skilled in the art thatthe scope of the present invention is not limited by what has been shownand described hereinabove, in conjunction with any of the embodiments.Rather, the scope of the invention is limited solely by the claims,which follow.

1. A flat plate heat exchanger which includes: a support structurehaving at least one elongate support member having a known width; and aplurality of generally flat plate members formed of a heat conductivematerial, and arranged for attachment to said at least one supportmember, so as to be supported thereby, each said plate member includingat least one edge portion, and at least one support engagement portionwhich includes: a recess formed in a predetermined one of said at leastone edge portion of said plate member, configured to at least partiallyaccommodate the width of said at least one support member, said recesshaving an outlet for admitting said at least one support member; and aflexible arm formed along a portion of the recess, terminating in alateral protrusion protruding inwardly into said recess, thereby toconstrict said outlet such that said recess outlet has a width that isless than the width of said at least one support member, said flexiblearm being operative in the presence of at least a predetermined lateralflexure force applied thereto to snap couple and decouple said platemember and said at least one elongate support member, and further, inthe absence of at least a predetermined lateral flexure force appliedthereto, to prevent coupling or de-coupling of said plate member fromsaid at least one support member, said flexible arm being furtheroperative to flex in a direction which is both lateral to the directionof coupling and de-coupling and in the plane of said plate member.
 2. Aflat plate heat exchanger according to claim 1, wherein said at leastone elongate support member includes a pair of spaced apart generallyparallel elongate support member, and each said flat plate member has apair of generally parallel edge portions each having formed therein asingle one of said at least one support engagement portion for couplingwith a selected one of said support members, and wherein said flat plateis configured such that, when a first of said support engagementportions is coupled with a first of said elongate support members, theother of said support engagement portions is coupled with the other ofsaid support members so as to define therewith a space in a directiongenerally parallel to an axis extending between said pair of elongatesupport members.
 3. For use in a flat plate heat exchanger having one ormore elongate support members of known width for supporting a stack offlat plate members, a flat plate member which includes: a generally flatplate portion formed of a heat conductive material; and at least onesupport engagement portion which includes: a recess formed in apredetermined one of said at least one edge portion of said platemember, configured to at least partially accommodate the width of one ofthe support members, said recess having an outlet for admitting thesupport member; and a flexible arm formed along a portion of the recess,terminating in a lateral protrusion protruding inwardly into saidrecess, thereby to constrict said outlet such that said recess outlethas a width that is less than the width of the support member, saidflexible arm being operative in the presence of at least a predeterminedlateral flexure force applied thereto to snap couple and decouple saidplate member and the elongate support member, and further, in theabsence of at least a predetermined lateral flexure force appliedthereto, to prevent coupling or de-coupling of said plate member fromthe support member, said flexible arm being further operative to flex ina direction which is both lateral to the direction of coupling andde-coupling and in the plane of said plate member.
 4. A flat platemember according to claim 3, wherein the elongate support apparatusincludes a pair of generally parallel elongate support members spacedapart along an axis, and each said flat plate member has a pair ofgenerally parallel edge portions each having formed therein a single oneof said at least one support engagement portion for coupling with aselected one of the support members, and wherein said flat plate isconfigured such that, when a first of said support engagement portionsis coupled with a first of the elongate support members, the other ofsaid support engagement portions is coupled with the other of thesupport members so as to define therewith a space along said axis,thereby to accommodate thermal expansion of said flat plate member.